Multi-OS booting after /boot/efi was reformatted

General system EndeavourOS installation
10

The laptop was setup using this guide by 2000:

https://forum.endeavouros.com/t/howto-gpt-uefi-install-with-full-disk-encryption-btrfsonluks-with-separate-root-home-and-pkg-subvolumes-hibernation-with-a-swapfile-auto-snapshots-with-easy-system-rollback-gui-boot-into-snapshots/

System snapshots are generated when upgrading (or optionally when booting) and grub can boot the machine into a snapshot, in case something wrong with updates.